Gallium nitride (GaN) offers substantial opportunity to enhance performance of electronic devices such as high electron mobility transistors (HEMTs) and metal-insulator-semiconductor field effect transistors (MISFETs). Epitaxial growth of GaN structures leads to phenomena associated with surface traps, which degrade performance of electronic devices, on the surface of the GaN structure. The surface traps are open bonding sites, on the surface of the GaN structure caused by an abrupt termination of the GaN crystal structure. The reactions associated with surface traps degrade the performance of electronic devices fabricated using the GaN structure by causing radio frequency (RF) dispersion and current collapse.
In order to avoid degradation of electronic devices due to the surface traps, a passivation layer may be deposited on the surface of the GaN structure. Generally, the passivation layer is a dielectric material capable of passivating, neutralizing, or filling the surface traps. However, conventional methods of passivating the GaN structure, such as plasma enhanced chemical vapor deposited (PECVD) silicon nitride, occur after the growth of the GaN structure and outside of the growth chamber used to grow the GaN structure. Therefore, the GaN structure is exposed to the atmosphere prior to fabrication of the electronic device. By exposing the GaN structure to the atmosphere, oxidation may occur on the surface of the GaN structure, thereby decreasing the effectiveness and reproducibility of the ex-situ passivation process. Therefore, there remains a need for a GaN structure having a passivation layer deposited before the GaN structure is removed from the growth chamber.